One example of a head mounted display (HMD) is an augmented reality (AR) HMD. There are many examples of fixed optics head mounted display headsets, which typically consist of a display or plurality of displays and relay optics which deliver computer generated graphics to the eyes of users. Additional fixed optics may be included that combines light from the real world and allow graphics to be overlaid over that which the user views in the real world. Subsystems are often associated with these displays to track the sight line of the user so as to provide information that drives the rendering of a CGI scene for view in stereo vision, simulating 3D vision.
However, consider the example of a HMD designed to operate as an AR HMD. It is possible that a user may desire to also play a virtual reality (VR) game. A problem arises in that HMDs are typically designed to work either as an AR headset or a VR headset but not both.